stability. Children increasingly gain the autonomy to select environments consistent with their genotype with age (Scarr & McCartney, 1983). Age-dependent gene expression is another possible explanation for relatively low genetic stability in childhood with increases into adulthood. As children mature, genetic effects may activate, while others deactivate, over child development, but remain in relatively consistent activation states across adulthood. Because genetic effects decrease in importance but also increase in stability, it is possible that any or all of these mechanisms occur simultaneously.
